Method of manufacturing strain-insulators.



T. SLOPER. v METHOD or MANUFACTURING smm INSULATORS. APPUCATION FILED MAR- 3', I915- 1,167,125. Patented Jan. 4, 1916.

' 4 SHEETS$HEET T. SLOPER.

METHOD 0F MANUFACTURING STRAIN TNSULATORS.- APPLICATION FILED MAR- 3], I9l5.

1,167,125. Patented Ja 1916.

4 SHEETS- T 2.

itt

METHOD OF MANUFAC G STRAIN INSULATORS. ILEDMAR. 3|, 1915- 1,167,125.

Patented Jan. 4, 1916.

4 SHEETS SHEET 3.

- q QMEKW T. SLOPER.- METHOD OF MANUFACTURING STRAIN-INSULATORS. APPLICATION FILED MAR. 31, 1915.

1,16 7,125..fl Ptented Jan.4,1916.

4 SHEETSSHEET 4.

" subject of the King of England, residing at FFEQE.

THUMAS SLO'PER, F DEVIZES, ENGLAND.

METHOD or manuraornarne sTnAm-insULATons.

- To all whom it may concern Be it known that l, THOMAS SLorER, a

Devizes, in Wiltshire, England, have in- ,vente'd certain new and useful Improve ments in Methods of Manufacturing Strainlnsulators, of which the following is a specification.

This invention is for improvements in or relating to themanufacture of strain insulators.

heretofore been built up by .winding rub- These insulators as used for aerials have bered thread (usually in the form of cord) on a former in the form of an elongated loop, the threads being pressed together by hand so that they adhered one to another, removing the loop thus built up from'the former and collapsing the sides together without closing the ends so that eyes were formed at the ends to receive thimbles or other fastening means. The insulator thus built up was then lashed at its ends and finally coated .with rubber and vulcanized. It has been found that in making up such insulators, the threads although laid parallel to each other when winding. them on the former, often got displaced during the further steps in the manufacture, so that theresulting insulator was weakened in, that all the threads did not take their proper proportion of the strain. 1

One object of the present invention is to provide an insulator built up as described above but by aprocess which insures that each thread shall take its proper proportion of the load.

Another object of the invention is to provide such an insulator which cannot bend unduly, as undue bending results in cracking the varnish with "which they are finally coated for the purpose of increasing their insulating properties. p

A press tool is used in carrying out the process, which tool however is not claimed herein but forms the subject of a separate application.

In the accompanying drawings :Figure 1 is a face-view of one end of an insulator constructed according to one method of carrying out, this invention; Fig. 2 is a section through the same on the line 22 of .Fig. 1; Fig. 3 is another section through the same insulator on the line 3.3 of'Fig. 2; Fig. 4 is a face-view of a modified form of insulator constructed according to this in- Specification of Letters Patent.

Application filed Mama 31,

Patented an. a, rare. 1915. Serial no. 18,324.

vention; Fig. 5 is a transverse section through a press-tool constructed according to this invention for carrying out the process of manufacture of the insulators; Fig. 6

shows the same section as Fig. 5 but with the parts in a different position; Fig. 7 shows a section similar to Fig. 5 but in a different plane with the parts in yet another position and a further element added, Fig. 8 is a section on the line 88 of Fig. 6. Fig 9 shows in part section yet another form of insulator according to this invention, and

.Fig. 10 shows a still further form of insulator according to-this invention.

The same letters indicate the same parts throughout the drawings.

In building up the insulators, rubbered threads A, such as are well-known from their use in the manufacture of Palmer cord tires, are first wound upon a former B, Figs. 58, which former in shape resembles a rectan ular bar havin rounded ends, and the thread is so wound upon it as to constitute when removed from the former an elongated loop, as can be seen by reference to Figs. 5-8.

lfhe threads are laid parallel to each other and in laying them as even a tension as possible is maintained throughout. The rubbered thread, as is known, is tacky, so that when laid together they will adhere to some extent to one another, but it has been found that pressing them together by hand does not cause them to adhere to one another sufficiently to prevent derangement during their removal from the former or during their" subsequent treatment. To cause them to adhere firmly to one another, the press-tool shown in Figs. 5-8 is therefore employed. Thistool comprises a basedie C and a cooperating die D. The basedie is provided with a through slot which at C is made to fit the former B but below this the slot is enlarged as shown at C The upper face of the die C is recessed about the slot at C the bottom part of this recess being made of such size and shape as to correspond to the size vand shape the lower half of the loop of thread A is required to take when compressed by the dies is required to take.

two or more pins E which register with and The die'D i's conveniently guided in the die C by pins D and may be connected'to the movable member of a press, or it may be operated merely by striking it.

The thread A is conveniently wound on the middle portion of the former B so that the former projects both above and below the loop as shown in Fig, 5. It fol-..

lows therefore that as the die D is'forced home, it first drives the former B partially through the loop and then compresses the thread so that the parts finally take the position shown-in Fig. 6.

The die D is provided with two or more perforations D which extend from its upper face through the tongue D so that a driver comprising a plate E and having slide through the perforations D can be employed to discharge the former B from the loop.

It will be appreciated that if the former and loop were taken out of the dies and then the loop removed by pulling it from.

been advanced and the former B is shown lying in the enlargement Q of the slot in the die 0. This enlargement is conveniently made of sufiicient depth to accommodate, the

former so that the dies may stand upon a flat surface if desired, while the former is being thrust out, and the former will then be found quite loose in the bottom of the die 0. The driver E is conveniently operated in the same press as is employed for consolidating the core. The loop of thread A is now removed from the dies and the two faces which rested on the sides of the former are collapsed together except at the ends-of the loop. These faces are fiat so that the two limbs of the loop can be made to unite as one. In Fig. 3, the threads A are shown "thus brought together and the space which occurs at each end of the limb is afterward filled with rubber A The rubber is not only made to fill the space, but also to surround a metal or other thimble A which is inserted in the eye to constistays with which it is intended to be used.

The thread A, after introducing the rubber A at the ends of the insulator, is lashed with a binding-thread A throughout/the whole of its length except the extreme ends wrapping of the thread stiffens the insulator so that it cannot easily be bent unduly. The whole of the insulator is finally covered with a coating of rubber F and then vulcanized, which makes all they parts adhere firmly together including the thimble A which thereby becomes firmly connected to the rubber-filling A and the exterior coating of rubber F.

The insulator is sometimes finally varnished to increase its insulating properties and the lashing of thread A which as before stated prevents undue bending of 'the insulator, thus acts to prevent cracking of the Varnish by any such undue bending.

The exterior of'the insulator may be variously formed according to requirements, for example, water-sheds G, Fig. 4, may be built up thereon. The water-shed shown in Fig. 4: is in the form of a flange of rubber or other material covered with rubber built up upon the insulator, and serves the purpose of throwing oif'drops of water which run down the insulator.

Fig. 9 shows an inverted cup-shaped water-shed H which may be built up on the insulator, and Fig. 10 shows a small ringshaped water-shed J. It will be appreciated that these water-sheds may take.

various forms according to requirements.

What I claim as my invention and desire to secure by Letters Patent is 1. In a process of manufacture of insulators for strainers from rubbered thread, the following steps, (a) winding the thread on a former to constitute an elongated loop, (6) placing the loop while still on the former between the movable dies of a press-tool shaped to the form it is desired the exterior of the loop shall take while still on the former, (0) compressing the loop between the said dies, and (d) removing the loopv from the former.

2. In a' process of manufacture of insulators for strainers from rubbered thread, the following steps, (a)winding the thread on a former to constitute an elongated loop, (7)) placing the loop while still on the former between the movable dies of a press-tool shaped to the form it is desired the exterior of the loop shall take while still on the former, (0) compressing the loop between the said dies, and (d) removing the loop from the former by driving the former out of the loop while the latter itself still remains between the dies of the press-tool.

3. In a process of manufacture of insulators for strainers from rubbered thread,

the following steps, (a) winding the thread on a former to constitute an elongated loop, (6) placing the loop while still on the former between the movable dies of a press-tool shaped to the form it is desired which are left open to form eyes, and (f) lashing the collapsed part of the loop around with thread from eye to eye.

4:. In a process of manufacture of insulators for strainers from rubbered thread, the following steps, (a) winding the thread on a former to constitute an elongated loop, (5) placing the loop while still on the former between the movable dies of a press-tool shaped tothe form it is desired the exterior of the loop shall take while still on the former, (a) compressing the loop between the said dies, (03) removing the loop from the former, (e) collapsing the limbs of the loop together except at the ends which are left open to form eyes, (f)

, inserting a thimble of hard material with a surrounding filling-piece in each eye, (g) lashing the collapsed part of the loop around with thread from eye to eye,'and (h) vulcanizing the whole of these parts'together.

5. a process of manufacture of insulators for strainers from rubbered thread, the following steps, (a) winding'the thread on a former to constitute an elongated.

loop, (1)) placing the loop while still on the former between the movable dies of a press-tool shaped to the form it is desired the exterior of the loop shall take while still on the former, (0) compressing the loop between the said dies, (03) removing the loop from the former, (c) collapsing the limbs of the loop together except at the ends which are left open to form eyes, (f) form- ,ing a laterally projecting water-shed on the strainer at a point between the eyes, and

(g) vulcanizing the water-shed on to the strainer when the whole is vulcanized.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS SLOPER.

I Witnesses:

HAROLD Pimsons I W. L. AVERIE. 

